3-Hydroxydecanoic Acid: A Natural Growth Regulator for Optimizing Wheat Development and Yield by Modulating Auxin and Gibberellin Pathways

This study investigated the effect of 3-hydroxydecanoic acid (3-HDA), a natural microbial-derived compound, on growth and yield of wheat (<i>Triticum aestivum</i> L.). Application of 3-HDA at 53 μM significantly enhanced seedling development, including increases in root length, fresh weight, and stem diameter. Moreover, it promoted tiller formation and elevated the chlorophyll content during the tillering stage. Notably, even at concentrations of up to 5.3 mM, 3-HDA exhibited no severe phytotoxic effects, indicating a broad safety margin. Field trials confirmed its efficacy, demonstrating substantial improvements in both grain number and weight per plant, with yield improvements ranging from 9.6 to 20.7% compared to untreated controls. The performance of 3-HDA outperformed that of the commercial seed-soaking agent epibrassinolide (eBL). Transcriptomic and RT-qPCR analyses revealed that 3-HDA upregulated auxin biosynthesis genes and signaling components, while it downregulated gibberellin biosynthesis. This dual hormonal modulation likely contributed to improved root architecture and tiller development, thereby enhancing the chlorophyll content, biomass accumulation, and ultimately grain yield. Overall, 3-HDA emerged as a promising, safe, and environmentally sustainable plant growth regulator for boosting wheat production.